Assertion: In an electrochemical cell anode and cathode are respectively negative and positive electrodes.
Reason: At anode oxidation takes place and at cathode reduction takes place.

Options

A. if both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false
D. If the assertion and reason both are false.

Explanation

To solve the question, we need to evaluate both the assertion and the reason given in the context of electrochemical cells.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that in an electrochemical cell, the anode is the negative electrode and the cathode is the positive electrode. This is true for galvanic cells (voltaic cells) where spontaneous reactions occur, generating electrical energy.

2. **Understanding the Reason**:
- The reason provided states that at the anode, oxidation takes place, and at the cathode, reduction takes place. This is also true and is a fundamental principle of electrochemistry. Oxidation involves the loss of electrons, which occurs at the anode, while reduction involves the gain of electrons, which occurs at the cathode.

3. **Connecting the Assertion and Reason**:
- The assertion is correct because, in a galvanic cell, the anode is indeed negative due to the excess of electrons (where oxidation occurs), and the cathode is positive (where reduction occurs). The reason supports the assertion by explaining the processes occurring at each electrode.

4. **Conclusion**:
- Both the assertion and the reason are true, and the reason correctly explains the assertion.

### Final Answer:
- **Assertion**: True
- **Reason**: True
- **Conclusion**: The assertion is correct because the reason provided is accurate.